the timing belt broke while driving and bent three exhaust valves on the left side . i had them replaced and had the head checked out , it was ok so i replaced it and the timing belt . when i started it ,it ran good for a few minutes and then it started to miss . i checked everything i could think of that i may or may not have done right . it still has a miss and runs like (excuse my language)@!*% .... can you help?